This invention relates in general to ball and socket joints and in particular to an improved bearing for use in such a joint.
Ball and socket joints are well known mechanical devices which are frequently used in vehicle suspension and steering systems. Such a joint typically includes a hollow cylindrical socket member having an opened end and a closed end. The closed end of the socket member has an aperture formed therethrough. A ball member of the joint is provided with a rounded head portion and a shaft portion extending therefrom. The joint is assembled by inserting the shaft portion of the ball member within the socket member and through the aperture formed in the closed end thereof. The head portion is retained within the socket member by a closure plate attached to the socket member to close the opened end. Frequently, one or more bearings are provided within the socket member to engage and support the head portion of the ball member. These bearings reduce the amount of friction between the two members. Also, the bearings frequently accommodate for looseness between the ball and socket members resulting from wear.
To further reduce the effects of friction and to prevent dirt and other contaminants from entering, the joint is usually provided with some means for injecting lubricant therein and for distributing such lubricant throughout the mating surfaces of the bearings and the head portion of the ball member. Many bearing structures have been developed with grooves formed in these mating surfaces for distributing the lubricant over the bearings and the head portion. Unfortunately, such grooves can become clogged or wear thin so as to prevent the passage of lubricant therethrough. Consequently, the service life of the joint may be greatly reduced. Furthermore, the presence of such grooves reduces the effective area of the mating surfaces of the bearings and the head portion. This reduced area lessens the load carrying capability of the joint and may shorten the service life of the joint. Lastly, because only a relatively small volume of lubricant can be injected into such grooves, frequent re-injection of lubricant is necessary to properly maintain the joint.